1. Technical Field
This invention relates generally to methods, systems and apparatus for managing digital communications systems.
2. Description of Related Art
Digital subscriber line (DSL) technologies provide potentially large bandwidth for digital communication over existing telephone subscriber lines (referred to as loops and/or the copper plant). In particular, DSL systems can adjust to the characteristics of the subscriber line by using a discrete multitone (DMT) line code that assigns a number of bits to each tone (or sub-carrier), which can be adjusted to channel conditions as determined during training and initialization of the modems (typically transceivers that function as both transmitters and receivers) at each end of the subscriber line.
In DSL systems using DMT modulation, both the transmitting and the receiving side must negotiate configuration parameters for data transmission during a phase called initialization or training before actual transmission of information. Important sets of parameters that need to be determined in all such systems before normal operation include power spectral density and bit allocation. Moreover, the ordering of the lines must also be determined for multi-line vectored systems. Deployment practice requires that DSL systems operate within certain constraints, such as data rate, margin, transmitted power, transmitted power spectral density and various related parameters. Existing methods for power spectral density determination and bit allocation are deficient in producing efficient solutions that meet all the above constraints. Efficient solutions for bit allocation, power spectral density determination and line ordering have previously not been proposed.
Systems, methods and techniques that permit efficient loading and/or ordering for single communication lines and vectored communication systems would represent a significant advancement in the art. Also, systems, methods and techniques that that can be easily integrated with, controlled by and/or assisted by a controller or the like likewise would represent a significant advancement in the art.